Internal combustion engine



1940- G. s. KAMMER I INTERNAL COMBUSTION ENGINE Original Filed Aug. 18,1937 Patented Jan. 23, 1940 PATENT OFFICE INTERNAL COMBUSTION ENGINEGeorge Stephen Kammer, Budapest, Hungary Original application August 18,1937, Serial No. 159,777. Divided and this application January 31, 1938,Serial No. August 28, 1936 187,998. In Germany 1 Claim. (Cl. 12333) Theinvention relates to internal combustion engines, more particularly ofthe compression ignition type, although it is not limited thereto.

The subject matter of the application is divided from the applicationSerial No. 159,777, filed on ,August 18, 1937.

In compression ignition engines the fuel is usually sprayed in by meansof pump pressure towards the end of the compression stroke, when thetemperature of the air in the working cylinder has already beencompressed up to the ignition temperature of the fuel. The manufactureof engines operating on this principle requires high precision andconsequently expensive workshop labor, so that the 'cost of smallengines especially is disproportionately increased.

Endeavors were made to avoid having fuel pumps working against the finalcompression pressure but no success was achieved in consequence of thepractical difficulties involved. Proposals were also made to produce thefuel and air mixture in a separate device outside the englue and then tointroduce it into the engine and there mix it with compressed air, butthese proposals did not lead to the desired result.

According to the invention the fuel'and air mixture is produced in theengine itself, namely in a mixing space or chamber arranged separatelyfrom the working space. The outlet pipe of the fuel pump or thecarburetter jet terminates in this separate chamber. the quantity offuel required for each working stroke the pressure of the air located inthe mixing chamber is lower than the final compression pressure. It mayfor instance be equal to atmospheric or only exceed the same slightly.Also the temperature of the air in this chamberis below the ignitiontemperature of the fuel. Consequently in the introduction of the fuelonly a slight excess pressure has to be overcome. As soon as the finalcompression pressure is reached, communication is established betweenthe working cylinder space and the mixing chamber so that the hightemperature air compressed by the working piston fiows from the formerinto the mixing chamber. The pressure is equalised between the twospaces and the fuel and air mixture ignites. Finally the gases arepushed out of the mixing chamber into the working cylinder.

The connection between mixing chamber and working cylinder is made inthe form of one or more ports or passages which are opened at certaintimes by a controlled member. The passing over of the contents of themixing chamber into the working cylinder is also carried out by actua-During the spraying in of tion at certain times of a controlled membersuch as a piston which as it moves forward, reduces the volume of themixing chamber practically to zero.

The two controlled members are combined by constructing the memberproducing the connection in the form of a valve or slider rigidlyconnected to the piston effecting the volume variation of the mixingchamber, e. g. in the form of a tubular valve provided with one or moreports. This control member is combined with the fuel pump so that itsmovement represents at the same time the stroke of the pump. To this endthe cylinder space of the fuel pump is formed as a hollow in the rodactuating the control member and by arranging for the pump piston to bestationary.

A fuel and air mixture poor in air is produced in the mixing space whichrequires the addition of more air for ignition. The fuel, however, has atendency to separate out from mixtures so poor in air or rich in fuel,particularly when the volume 'is reduced. The volume of the mixingchamber and the quantity and pressure of the air contained in it whenthe fuel is sprayed in are therefore given such values that noseparation of fuel from the gas mixture takes place even at full load,i. e. at the largest fuel consumption; as a precaution the temperatureof the mixture is increased by supplying heat.

Advantageously the mixing chamber obtains its air filling from theworking cylinder during or after scavenging.

When the air is introduced into the mixing chamber and when the contentsof the mixing chamber are introduced into the working cylinder, the fiowis in directions deviating from the radial in order to produce awhirling movement and make the mixture more effective.

The drawing illustrates by way of example several constructional formsof an engine according to the invention.

Figures 1 and 2 are sections of two difierent forms taken through theaxis of the working cylinder with the piston at the upper dead center.

Figure 3 is a transverse section of the form shown in Figure 1.

Figure 4 shows a modified detail of the structure illustrated in Figure2.

The method of operation of the constructional forms shown in Figures 1and 2 will be described with reference to a two-stroke cycle engine withself ignition while Figure 4 is directed to a modification whereinignition is brought about by means of an electric spark.

In the arrangement shown in Figures 1 and 2 when the working piston l isin the neighborhood of its lower dead centre it uncovers the usualadmission and exhaust ports (not shown) located near the lower limit oftravel of the piston, and through them the working cylinder is scavengedwith fresh air in the usual way. At the same time an auxiliary piston 2is shifted from its upper limiting position downwards, so that a mixingchamber 3 above the piston increases in volume, the pressure thereindiminishes and air flows into the chamber 3 through a port 5 in acontrol member constructed as a tubular valve extension of the auxiliarypiston 2. As may be seen from Figure 3, the axes of the passage 4 andthe port 5 are set away from the radial direction of the cylindricalchamber 3, so that the air entering the chamber 3 is set into a whirlingmovement.

A hollow space In is provided in the rod 6 of the auxiliary piston toact as the cylinder of a fuel pump. The cylinder I contains a piston 1which remains stationary even during the movement of the rod 6. Theupward tubular projection of the auxiliary piston 2 as 'it shiftsdownwards closes the passage 4 and at the same time the piston 1 entersthe space I0, which has been filled with fuel entering through the pipe8, and the apertures 9 in the rod 6, and presses the charge of fuelthrough a passage H into a jet 22. The fuel atomised by the jet thenpasses into the space 3. The passage II is closed by a spring loadednon-return needle valve (not shown) opening towards the chamber 3.

As the working piston I moves upwards and closes the exhaust andadmission ports in the usual way, it compresses the air in the cylinder.During this process the auxiliary piston 2 reaches its lower limit oftravel, so that the spraying in of fuel comes to an end. Thereupon thepiston 2 commences its upward travel. The mixture located in the chamber3 can have heat imparted to it through the walls by suitableconstruction of the engine parts bounding the chamber 3, advantageouslyalso by cooling the same to a less degree than usual, so that no fuelseparation occurs even during the compression. When the finalcompression pressure is reached in the working cylinder, the portarrives at the level of the axis of the passage 4, the compressed hotair flows into the chamber 3, the pressure is equalised and at the sametime combustion commences. In consequence of the combustion the pressurerises in the chamber 3 and consequently the flow reverses in the passage4. For the purpose of ensuring a whirling movement the axis of thepassage 4 is set at an angle to the radial direction of the combustionchamber it (Figure 3). In the meantime the auxiliary piston 2 continuesits upward travel until it reaches its upper limit as shown in Figure 1,so that it pushes the partly burnt gases out of the chamber 3 throughthe port 5 and the passage 4 into the working cylinder. Accordingly thecombustion process takes place principally in the chamber l6. During thesubsequent working stroke of the piston l, as also during the scavengingof the working cylinder, the auxiliary piston 2 remains at its upperlimit of travel, and at this time the volume of the chamber 3 ispractically zero. The auxiliary piston 2 only commences to movedownwards again when the scavenging process of the working cylinder withfresh air has already taken place. From then onwardsthe processes arerepeated in the sequence already described.

The dimensions in the stroke direction of the stationary passage 4 andof the movable port 5 are so arranged that the communication of theworking cylinder with the chamber 3 is established at the correct pointof time and is retained as long as necessary.

The quantity of fuel to be introduced per working stroke in dependenceon the load on the engine is regulated by displacing the piston 1 whichis otherwise stationary during operation. So long as the top face I2 ofthe piston 1 is at the same level as the top of the apertures 8 in therod 6 the piston 1 presses no fuel into the passage l I. Fuel issupplied only when the face l2 of the piston 1 enters the hollow l0. Anyspraying in of fuel therefore only takes place during that portion ofthe unvaried stroke of the rod 6 which is determined by the position ofthe face l2. The piston 1 can be adjusted as to location to vary thefuel feed by shifting a double-armed lever I4 projecting through a slotl3 in the rod 6.

The engine shown in Figure 2 operates by the so-called whirling chambermethod. In this case the auxiliary piston l1 and the control member inthe form of a tubular valve take up their lower limiting position whenthe working piston I5 has reached its upper dead centre. in thisposition a port I!) in the piston I1 comes into register with thepassage I8 and the compressed air fiows from the working cylinder to thechamber 20, where the mixture ignites. In consequence of the pressureincrease due to combustion the flow in the passage I8 is reversed. Theauxiliary piston I 1 remains during the workmg stroke of the piston l5at its lower limit of travel and the combustion therefore takes placeprincipally in the mixing chamber 20. The auxiliary piston I! onlyreaches its upper limit of travel when the working stroke is nearlycompleted. In doing so it pushes the products of combustion out of thechamber 20 through the passage 2| into the working cylinder whence theyare removed in the scavenging process. After this has occurred theauxiliary piston l1 again shifts downwards and draws fresh air into thechamber 2|] from the working space I through another passage 2 I.

When the arrangement according to the invention is applied to four-cycleengines, the auxiliary piston draws the air out of the working cylinderduring the suction stroke of the working piston.

The movement of the auxiliary piston described in the examples ofconstruction can be attained at for instance by means of a cam.

The arrangement shown in Figure 4 is designed for use in enginesconstructed according to Figure 2 but wherein the structure of the aircompressed in the working cylinder does not reach the ignitiontemperature of thefuel. Therefore, after communication is establishedbetween the working cylinder space and the mixing space, the mixturemust be ignited, that is to say, by means of an electric spark, forwhich purpose a spark plug '23 is shown in position in the cylinderhead.

I claim:

An internal combustion engine comprising a working cylinder and piston,a mixing chamber casing immediately beyond the-working cylinder, amixing chamber formed within said casing, a fuel jet terminating in saidchamber. a member movable to vary the volume of the chamber and providedwith a port to register in the minimum volume position with a passagecommunicating with the working cylinder, 9, rod connecting the saidmember to timed operating means. the rod With the parts being hollowedto form a fuel pump cylinder the member being movable from beyond thecommunicating with the jet, means for admitting casing to change thenormallyoperative vertical fuel to the fuel pump, a piston to cooperatewith position of the piston within the fuel pump cylinthe fuel pumpcylinder, and a member extending der. 1

6 through the casing with one end cooperating with GEORGE STEPHEN KAMMER5 the piston to hold the latter fixed in operation,

